********************************************************
NOTICE
********************************************************
This document was converted from
WordPerfect or Word to ASCII Text format.
Content from the original version of the document such as
headers, footers, footnotes, endnotes, graphics, and page numbers
will not show up in this text version.
All text attributes such as bold, italic, underlining, etc. from the
original document will not show up in this text version.
Features of the original document layout such as
columns, tables, line and letter spacing, pagination, and margins
will not be preserved in the text version.
If you need the complete document, download the
WordPerfect version or Adobe Acrobat version, if available.
*****************************************************************
Before the
Federal Communications Commission
Washington, D.C. 20554
In the Matter of )
)
Digital Audio Broadcasting Systems )
And Their Impact On the Terrestrial Radio ) MM Docket No. 99-325
Broadcast Service. )
NOTICE OF PROPOSED RULE MAKING
Adopted: November 1, 1999 Released: November 1, 1999
Comment Date: [75 days from the date of publication in the Federal Register]
Reply Date: [105 days from the date of publication in the Federal Register]
By the Commission:
Table of Contents:
Paragraph
I. Introduction 1
II. Background
A. The Current Radio Broadcast Service and the Commission's Commitment
to Enabling Broadcasters to Convert to Digital Transmissions. 4
B. The Present Development of In-Band On-Channel ("IBOC") and
Other Digital Audio Broadcasting ("DAB") Systems. 7
C. The USA Digital Radio Petition and Comments. 12
III. Discussion
A. DAB Policy Goals. 15
B. Tentative Selection Criteria for a DAB System. 20
C. IBOC DAB Model. 36
D. DAB Model Utilizing New Spectrum. 40
E. Standards and Testing.
1. DAB Transmission Standard. 50
2. Decision-Making Models for DAB System Testing, Evaluation and
Transmission Standard Selection. 54
IV. Administrative Matters 59
Appendix A: Initial Regulatory Flexibility Analysis
I.INTRODUCTION
1. Digital audio broadcasting ("DAB") technology is in various stages of development and
implementation throughout the world. Its proponents claim that it has the capacity to move the
American radio broadcast service "to the next plateau of audio performance by providing listeners
with enhanced sound quality more closely resembling original source material and digital
recordings." DAB technology utilizes new and efficient audio compression techniques that reduce
the amount of bandwidth required to transmit a high-quality audio signal. In addition, DAB
transmission systems can be designed to achieve the same coverage as analog signals at lower
powers, and to achieve greater robustness to interference and other impairments. Proponents also
contend that a DAB system would enable radio broadcasters to offer the public an array of new
auxiliary services. Thus, DAB technology has the potential to significantly enhance the American
radio broadcast service.
2. The Commission is initiating this rule making proceeding to consider alternative
approaches to introducing DAB service to the American public. The catalyst for this action is the
progress of in-band, on-channel ("IBOC") DAB technology, which IBOC system proponents assert
is in a final stage of development. IBOC systems are designed to allow the simultaneous
broadcast of analog and digital radio signals in the AM and FM bands without disrupting existing
analog service. IBOC DAB systems have not been conclusively proven to be technically viable at
this point in time, yet great strides have been made and the systems certainly hold real promise. It
is helpful for the Commission to determine whether an IBOC model and/or a model utilizing new
radio spectrum would be the best means of promptly introducing DAB service in the United States.
By initiating this proceeding now, we can foster the further development of IBOC systems, as well
as new-spectrum DAB alternatives, help DAB system proponents identify design issues of public
interest dimension and, where possible, encourage modifications that advance these policy
objectives. We also can begin developing a complete record regarding the issues raised by this new
technology. The resolution of these issues will shape fundamentally the nature of our radio
broadcast service for years to come, and we intend to be in a position to act expeditiously when the
time is ripe.
3. In this Notice, the Commission: (1) reaffirms its commitment to provide radio
broadcasters with the opportunity to take advantage of DAB technology; (2) identifies Commission
public policy objectives for the introduction of DAB service; (3) proposes criteria for the
evaluation of DAB models and systems; (4) evaluates IBOC and new-spectrum DAB models; (5)
inquires as to the need for a mandatory DAB transmission standard; and (6) considers certain DAB
system testing, evaluation and standard selection issues.
IV.BACKGROUND
A. The Current Radio Broadcast Service and the Commission's Commitment to
Enabling Broadcasters to Convert to Digital Transmissions.
2. The Commission often has recognized the importance of our free, over-the-air radio
broadcast service, with its unrivaled accessibility and unique ability to provide local news,
information and public service programming. Although this vital communications service
continues to grow and prosper, it faces significant technical limitations and competitive
challenges. Opportunities for new and improved FM service are limited by spectrum congestion in
most major and mid-sized radio markets. The Commission has proposed a new, low power FM
("LPFM") service, but acknowledged that there may be difficulty finding sufficient spectrum for
the new service. With regard to the AM band, we have recognized that "many stations currently
experience significant interference and degraded reception[.]" The radio broadcast service also
faces competitive challenges from new digital audio technologies offering consumers enhanced
sound fidelity and other services, including the recently-authorized satellite digital audio radio
service ("satellite DARS"). Many have argued that the Commission must provide radio
broadcasters with the opportunity to convert to a digital platform to enable them to compete
effectively and to ensure the continued viability of this important service.
3. In 1990, the Commission opened a proceeding to consider the authorization of digital radio
services. The proceeding initially addressed both a satellite DARS and a terrestrial DAB service.
As the record developed, however, it became evident that the IBOC DAB systems then under
consideration for a terrestrial service were not technically feasible, and the proceeding ultimately
focused on satellite DARS spectrum allocation, service and licensing issues. Nevertheless, the
Commission advanced several principles relevant here. Most importantly to the instant proceeding,
the Commission emphasized its conviction that "existing radio broadcasters can and should have
the opportunity to take advantage of new digital radio technologies[.]"
[W]e anticipate that technical advances will soon permit both AM and FM
broadcasters to offer improved digital sound. . . . Some of the systems being tested
are designed specifically to permit digital broadcasting within the existing AM and
FM bands. We fully support these developments, and we see great promise in these
innovations for providing improved services to consumers. These innovations will
also help promote the future viability of our terrestrial broadcasting system, which
provides local news and public affairs programming.
The Commission also expressed its willingness to "act expeditiously to consider any appropriate
changes to our rules" when the time was ripe.
4. In addition, the Commission emphasized localism as a "touchstone value" of the terrestrial
radio broadcast service. Many radio broadcasters argued that authorization of a satellite DARS
would have an adverse impact on the existing radio broadcast industry. Some also argued that
satellite DARS should be delayed until a terrestrial DAB system was close to implementation. In
rejecting such arguments, the Commission stated that "[o]ur concern about licensing satellite
DARS focuses on its impact on the provision of locally oriented radio service." In this regard, it
concluded that "the record does not demonstrate that licensing satellite DARS would have such a
strong adverse impact that it threatens the provision of local radio service." Although the
Commission recognized that the two services would compete to some extent, it found that the new
satellite DARS would complement existing, local radio broadcasting stations by providing regional
and national services.
E. The Present Development of IBOC and Other DAB Systems.
6. Current IBOC system designs. As stated above, IBOC systems are designed to allow the
simultaneous broadcast of analog and digital signals in the AM and FM bands without disruption
of existing analog service. The Commission's rules impose limits or "emission masks" on the
power of a station's signal inside and outside its assigned channel. Together with minimum
spacing requirements, emission masks prevent interference by limiting a station's signal strength
relative to other, nearby stations operating on co- and adjacent channels. These limits are based on
analog signal transmissions centered on their assigned channels. In the "hybrid" operational mode,
IBOC systems transmit lower power digital signal "sidebands" that are positioned on either side of
the host analog signal. The digital signal waveforms are designed to conform to the current
emission masks. Digital signals would be interleaved: station A's upper digital sideband would
be located between 1st adjacent channel station B's lower and upper digital sidebands, and
adjoining station B's carrier frequency. In addition, the presence of digital sidebands would
reduce the separation between the host analog signal and 2nd and 3rd adjacent channel digital
signals. IBOC system proponents believe that digital signal processing techniques will permit the
transmission of a digital "pair" of each analog signal in the AM and FM bands, without disrupting
existing analog service. Their systems purportedly will provide near CD-quality sound on FM
channels and FM-quality sound on AM channels, coverage equal to or greater than that provided
by analog transmission systems, and enhanced auxiliary capacity.
7. IBOC systems also have an "all-digital" mode. As a result of significant differences in the
design of the USA Digital Radio, Inc. ("USADR") and Lucent Technologies, Inc. ("Lucent") all-
digital systems, the transition from hybrid to all-digital operations under each system also would
differ. After a transition to all-digital operations, the USADR system would continue to divide
the digital signal into sidebands, boost power by tenfold, and utilize the channel center formerly
occupied by the host analog signal for lower-power auxiliary services. Because of the increased
power of the signal sidebands, the all-digital transmissions likely would interfere with 1st adjacent
channel analog signals. Accordingly, USADR proposes to restrict digital stations to hybrid
operating parameters for a period of 12 years to provide a reasonable transition to an all-digital
radio broadcast service. At the end of this transition period, USADR proposes a sunset on
protection of analog signals, with the initiation of "all-digital" signals. In contrast, Lucent's
system would largely consolidate the all-digital signal in the channel center, utilizing the 1st
adjacent channel areas formerly occupied by the digital sidebands for auxiliary services. Under
this system, no sunset on analog protection would be necessary because all-digital transmissions
would be expected not to interfere with other stations' analog signals, and broadcasters would be
able to initiate all-digital service at any time.
8. Recent IBOC DAB system developments/NRSC process. During the mid-1990s, the
National Radio Systems Committee ("NRSC") established a DAB Subcommittee which, in
collaboration with a Consumer Electronics Manufacturing Association ("CEMA") Digital Audio
Radio Subcommittee, oversaw laboratory tests of a number of IBOC systems, ultimately
concluding that none were technically viable. CEMA also oversaw laboratory and field testing of
non-IBOC DAB systems, including a Eureka-147 system operating in the L-Band (1452-1492
MHz). CEMA's December, 1997 Final Report ("CEMA Final Report") stated that the IBOC
systems tested exhibited two major deficiencies: (1) poor digital audio performance under impaired
signal conditions; and (2) incompatibility with analog FM service.
9. IBOC system proponents now contend that they have made substantial progress towards
developing technically viable IBOC systems. In its Petition, USADR describes computer model
simulations demonstrating that its system design satisfies its own performance requirements,
including improved performance over, and compatibility with, existing analog service. USADR
acknowledges that laboratory and field testing also are necessary to demonstrate the system's
viability. It states, however, that it expects to complete such testing before the end of the year
and that "preproduction systems will be operational beginning in early 2000," with the capability
of commencing commercial service later that year. Likewise, Lucent states that "substantial
progress has been made in 1999 toward completing our IBOC system design and having it
demonstrated in the laboratory and in the field[,]" and that "[a] completely tested and ready IBOC
digital system is only months away." In light of the system proponents' progress, the NRSC has
reactivated its DAB Subcommittee and developed model IBOC laboratory and field test
guidelines. The IBOC system proponents reportedly have agreed on a December 15, 1999
deadline for submission of certain test results to the NRSC. In contrast to the CEMA Final
Report, which compared systems based on a number of performance objectives, this first phase of
NRSC testing appears to be designed to demonstrate the technical viability of IBOC systems, that
is, "to establish whether or not IBOC DAB systems are a significant improvement over existing
AM and FM analog radio services[,]" as well as whether IBOC systems can operate without
disrupting analog service.
10. Eureka-147 DAB systems. DAB systems are now being implemented in Canada, Europe,
and elsewhere utilizing what is referred to as "Eureka-147" technology. Eureka-147 systems
utilize a wide bandwidth, are capable of transmitting multiple audio channels, and can operate on
various frequencies. Rather than the FM band, the services that have been introduced in Europe
and Canada are using other frequencies, such as the "L-Band" (1452-1492 MHz) and "Band III"
(around 221 MHz). In the United States, however, the L-Band is allocated for the purpose of
flight test telemetry, and the spectrum around 221 MHz is allocated for the primary purposes of
land mobile and amateur use. The CEMA Final Report found that "[o]f all the systems tested,
only the Eureka[-147] system offers the audio quality and signal robustness performance that
listeners would expect from a new [DAB] service in all reception environments." No proponent
of a Eureka-147 or other non-IBOC DAB system has filed comments in response to USADR's
Petition. We currently are unaware of any such proponents in the United States.
K. The USADR Petition and Comments.
12. The USADR Petition for Rulemaking was filed on October 7, 1998, and placed on public
notice on November 6, 1998 (RM-9395). In the Petition, USADR urged the Commission to take
the following regulatory steps:
(1) "find[] that the public interest would be served by the introduction of DAB and
that IBOC is the most appropriate means to implement DAB in the United States[;]"
(2) adopt rule changes "to insure the compatibility of analog and digital radio
stations[;]" (3) adopt "a transition plan that provides appropriate protection for
analog radio for an interim period but also fosters the transition to an all-digital
environment[;]" (4) "find[] that it will adopt a DAB transmission standard that will
insure that all DAB radios are compatible with all DAB transmitters[;]" (5) "establish
criteria for evaluating IBOC systems and a timetable for the submission of IBOC
system information to the Commission for evaluation[;]" and (6) "select a single
IBOC system to be implemented . . . and adopt a transmission standard that will
allow implementation of the selected system."
13. Twenty-three comments and six reply comments were filed in response to the Petition.
Commenters expressed nearly unanimous support for the introduction of DAB. IBOC system
proponents and many radio broadcasters also endorsed IBOC as the best means of implementing
DAB in the United States, provided that its compatibility with existing analog service is
demonstrated. CEMA, National Public Radio, Inc. ("NPR") and a number of public interest
groups, however, urged the Commission to carefully consider non-IBOC DAB systems utilizing
new spectrum, such as a Eureka-147 system. With regard to USADR's proposed step (2), the
comments reflected a broad consensus that until laboratory and field tests demonstrate the
compatibility of the current generation of IBOC systems with analog service, consideration of
specific rule changes to implement IBOC is premature. Several commenters noted that the
Commission cannot consider specific rule changes until it selects a specific DAB system.
Likewise, with regard to (3), the need to establish a sunset on analog signal protection may depend
on the selection of an IBOC system.
14. With regard to USADR's proposed step (5), many commenters agreed that the
Commission has a role to play not only in the implementation of DAB, but also in fostering the
further development of IBOC DAB systems. The commenters suggested various models for such
Commission action, including the mandatory submission of test results that would be evaluated in
the context of a notice-and-comment rulemaking proceeding and the creation of an advisory
committee with open membership. Finally, with regard to (4) and (6), the commenters generally
agreed with USADR that a single DAB transmission standard ultimately will be required to ensure
a successful transition to digital.
XV.DISCUSSION
A. DAB Policy Goals.
2. It has been several years since the Commission last considered terrestrial DAB issues.
Accordingly, we believe it will be useful to set forth the public policy objectives that will guide our
deliberations in this proceeding. We begin with the settled determination that fostering the
development and implementation of terrestrial DAB is in the public interest. We believe that the
principles advanced by the Commission in Docket No. 90-357 regarding the terrestrial radio
broadcast service remain valid, and will look to them in developing our approach to a terrestrial
DAB service. The goal of introducing terrestrial DAB service is most fundamentally grounded
on the promise of digital technology to provide vastly improved radio service to the public. It is
our goal to authorize a DAB service that permits broadcasters and listeners to realize fully the
superior technical performance capabilities of this technology.
3. The Commission also remains firmly committed to the related goals of "supporting a
vibrant and vital terrestrial radio service for the public" and creating DAB opportunities for
existing radio broadcasters. We must ensure that the introduction of DAB does not weaken the
vitality of our free, over-the-air radio broadcast service, which provides service to virtually all
Americans through a strong, independent system of privately owned and operated stations. We
previously recognized the close relationship between this goal and providing digital opportunities
for existing broadcast licensees in the digital television ("DTV") proceeding, where we concluded
that "implement[ing DTV] within the existing framework of local television broadcasting" would
be the best way to preserve the unique benefits of the local television broadcast service. We also
concluded that existing television broadcasters were the group best suited to introduce this new
service to the public "in the quickest and most efficacious manner." We believe that the same
reasoning applies here. In addition, as was the case with the DTV transition, we believe that it is
desirable for all broadcasters to have the opportunity to provide DAB service. We recognize,
however, that prior to the selection of a DAB system and spectrum, we cannot know whether this
goal is feasible and what trade-offs it may require.
4. A viable DAB system must be spectrum efficient. Our preference is for DAB systems
that use the least spectrum. It is the Commission's obligation to ensure that the value derived from
the superior transmission capabilities of DAB technology is allocated in a manner consistent with
the public interest. In addition, with regard to IBOC DAB systems, we believe that a transition to
an all-digital service is an appropriate public policy goal, because the spectrum efficiencies and
related new service opportunities inherent in such systems can be realized fully only in an all-
digital operational mode.
5. Finally, it is our objective to foster a rapid and non-disruptive transition to DAB for
broadcasters and listeners. A viable system must minimize interference to analog AM and FM
stations during that period when digital and analog service operate concurrently. The
Commission also will favor systems that do not require burdensome investments in new broadcast
transmission equipment. Additionally, we recognize that a viable DAB model should provide
broadcasters with sufficient incentives to convert to DAB so that the American public receives the
benefits of this new technology as soon as possible. A non-disruptive transition for consumers
must protect listeners' investment in over one-half billion radio receivers. Thus, a transition
period of some reasonable duration appears necessary to permit the graceful obsolescence of this
equipment. It is equally important that the Commission's DAB technical rules make it possible for
manufacturers to produce reasonably-priced digital receivers.
6. One other issue warrants mention at this point. The Commission previously has noted the
advantages of an IBOC DAB approach. As explained in more detail below, we continue to
believe that IBOC systems hold great promise. These systems may be able to facilitate a seamless
transition to an all-digital radio broadcast environment by affording all broadcasters a concurrent
digital and analog broadcast opportunity. Moreover, IBOC is the only approach that, to date, has
attracted a substantial number of adherents. Nevertheless, this Notice should not be construed as
the start of an IBOC rulemaking. CEMA correctly frames the issue: the Commission's challenge
is to craft a terrestrial DAB service that meets both demanding performance objectives and the
public's expectations. We agree with NPR that at this time it is not possible to definitely settle
this issue in favor of IBOC.
G. Tentative Selection Criteria for a DAB System.
8. We seek to determine which DAB model and/or system would best promote our above-
stated public policy objectives. In reaching this fundamental determination, we propose to apply
the following evaluative criteria: (1) enhanced audio fidelity; (2) robustness to interference and
other signal impairments; (3) compatibility with existing analog service; (4) spectrum efficiency;
(5) flexibility, (6) auxiliary capacity; (7) extensibility; (8) accommodation for existing
broadcasters; (9) coverage; and (10) implementation costs/affordability of equipment. The order of
these proposed criteria is not intended to imply a hierarchy among them.
9. (1), (2) Enhanced audio fidelity/robustness. Consumer demand for improved audio
fidelity is undeniable. Access to superior digital audio technologies, such as compact discs and
in the near future satellite DARS, and the perceived benefits of digitalization generally, fuel such
demand. We believe that an important benefit of DAB will be enhanced sound quality. DAB
technology should permit significant improvements in audio fidelity and robustness over our
current analog service. For example, USADR and Lucent anticipate that AM hybrid IBOC DAB
systems will offer sound quality comparable to today's stereo FM systems, and that FM hybrid
IBOC DAB systems will deliver near-CD quality sound. As to robustness, DAB systems may
improve reception by using techniques that protect digital signals from many forms of impairment
that affect analog signals. We seek comment on these selection criteria, including the specific
standards that should be used to compare competing systems.
10. IBOC systems are designed to operate in two fundamentally different RF environments. In
the hybrid mode, an IBOC system must make certain trade-offs to avoid interference to in-band
analog transmissions. Although the sharing of spectrum may facilitate a transition to DAB, it may
also result in lesser digital performance during the transition period. Accordingly, a comparison of
IBOC and new-spectrum alternatives must consider the time frame within which either system
could achieve all-digital operations and the short-term performance advantages, if any, of hybrid
IBOC digital systems over the current analog service. We seek comment on this issue. A related
question is whether the trade-offs necessary to permit IBOC digital transmissions in the hybrid
mode would extend into the all-digital world, i.e., limit the potential for enhanced audio fidelity and
robustness in comparison to non-IBOC alternatives. We seek comment on the appropriate ways of
comparing IBOC and new-spectrum DAB alternatives under these selection criteria.
11. (3) Compatibility. A DAB system must be compatible with the continued operation of
existing radio broadcast stations. This appears to be a criterion of relevance primarily to in-band
systems. Most commenters agree with NAB's position that "the implementation of an IBOC
DAB service that causes significant impairment to existing analog service would raise serious
questions as to the suitability of the system." We tentatively conclude that IBOC systems should
minimize interference to reception of host and adjacent-channel analog signals during hybrid mode
operations including, for FM stations, interference to subcarriers.
12. To a significant extent, the opportunity to introduce new ancillary services in both the
USADR and Lucent systems is tied to the initiation of all-digital operations. In this regard,
however, it appears that the Lucent and USADR systems differ in one important respect. Unlike
Lucent's, USADR's all-digital mode transmissions could interfere with an adjacent channel station
transmitting an analog signal. As a result, initiation of all-digital operations under USADR's
system would not be possible until a fixed analog "sunset" date, i.e., a date when stations
transmitting analog signals would lose their current interference protection. A system that permits
stations to implement rapidly an all-digital radio service may serve the public interest better than
one that delays the opportunity to fully realize the benefits of DAB until the end of what is likely to
be an extended transition period. On the other hand, we recognize the potential benefit of a fixed
analog "sunset" date in fostering a transition to an all-digital service. We seek comment on
whether, with regard to an IBOC system, all-digital compatibility with analog signals should be an
evaluative criterion.
13. We also seek comment on the compatibility of IBOC systems and the proposed low power
FM ("LPFM") service. In our LPFM Notice, we recognized the importance of taking into
consideration "the implications of 2nd-adjacent channel protection for the possible conversion" to a
DAB system. We asked whether we should impose a 2nd adjacent channel protection requirement
on LPFM stations "for the purpose of protecting a possible future digital radio technology,
considering that creating opportunities for new radio service is also an important Commission
goal." Similarly, we ask here how a DAB system could be designed to protect a possible future
LPFM service. Both Lucent and USADR expressed concern about the impact of LPFM on DAB
but it appears that the possible relaxation of 3rd adjacent channel protection standards for LPFM
would have no material impact on digital signal reception. "Because of the design of the USADR
IBOC system, digital reception is essentially not susceptible to third adjacent channel interference;
nor is IBOC likely to increase the potential for causing such interference to analog stations."
Specifically, we seek comment on the potential for enhancing the robustness of IBOC systems to
reject undesired 2nd and 3rd adjacent channel signals, and the likely impact of such modifications.
14. (4) Spectrum efficiency. The Commission is committed to establishing a spectrally-
efficient terrestrial DAB service. We recognize that certain basic design and regulatory trade-offs
are inherent in all analog and digital systems. As Lucent observes, "there are multiple different
pairings of attributes possible that would be capable of delivering digital audio in an IBOC
configuration." Lucent and USADR assert that IBOC is spectrum efficient in the sense of not
requiring additional spectrum to implement digital transmissions. They also contend that IBOC
would not encumber additional spectrum because the IBOC signal would be contained by the
emission masks for the analog channels and has been developed around the existing analog
interference protection criteria. However, spectrum efficiency as a selective criterion also concerns
the additional value that results from the transition from an analog to a digital transmission service.
In the instant context, the added value of spectrum is the product of several factors. These include
the capacity of digital technologies to transmit greater amounts of data per hertz, enhanced
flexibility, the ability to design digital systems that are less likely to cause interference, less
susceptible to interference, and more robust with respect to multipath fading and non-radio noise
sources, and the capacity to provide a listenable service at relatively low signal strength levels.
15. This proceeding also presents an opportunity to consider the spectral efficiencies that could
be realized by advances in receiver technology over the decades since the analog interference
standards were established. We note that analog receivers can now be designed with improved
frequency selectivity to better reject potentially interfering signals on adjacent channels.
Although IBOC systems are based on existing analog protection criteria, we wish to examine the
extent to which state-of-the-art receiver technology may provide additional protection against
interference, and thereby facilitate more intensive spectrum utilization. What would be the
additional cost to consumers of receivers with state-of-the-art immunity? Are there design
considerations other than cost that would practically limit interference immunity?
16. At this preliminary stage, it is clear that the Commission needs additional information
about the specific mix of DAB design attributes that could best meet the current and future needs
of all stakeholders in our free, over-the-air broadcasting system. Therefore, we seek comment on
possible DAB spectrum efficiency standards. Are any of the Eureka-147 DAB and/or satellite
DARS signal bandwidth and interference protection standards relevant in establishing DAB
spectrum efficiency standards for IBOC and/or non-IBOC DAB systems? What bandwidth is
necessary for DAB systems to achieve CD-quality audio signals? What are the spectrum
implications of recent advances in coding and multistreaming technologies on the ability to deliver
CD-like audio quality? With regard to each proponent's DAB system, what are the quantifiable
trade-offs between bandwidth and signal robustness? What power, interference, and bandwidth
trade-offs should the Commission consider in balancing the needs of incumbents and potential new
entrants? Should there be different data capacity criteria during and after the transition to all-
digital operations? Would the transition to all-digital service be slowed if incumbents were
assigned less bandwidth for all-digital operations than their current channel assignments? Is
preserving (or expanding) current AM and FM bandwidth assignments necessary for consumers to
receive the full benefits of DAB, including a rapid implementation of an all-digital DAB system?
17. (5), (6) Flexibility/auxiliary capacity. Flexibility is one of the principal benefits of digital
technology. Many commenters believe that increasing radio broadcasters' capacity to provide
auxiliary services will be an important benefit of DAB technology. The Commission is committed
to encouraging a DAB system design that would permit the flexible and dynamic development of
new broadcast and non-broadcast services and features and allow broadcasters to realize specific
service opportunities. We currently provide broadcasters with a great deal of freedom with regard
to subcarrier usage and believe that a similar approach to regulating augmented auxiliary capacity
would likewise be in the public interest.
18. In this regard, the Telecommunications Act of 1996 requires the Commission to permit
DTV licensees to provide ancillary or supplemental services, so long as such services do not
derogate the free television broadcast service, and to assess and collect a fee for such use when the
licensee receives fees or other compensation from third parties. We tentatively conclude that the
provision of new and innovative ancillary services must not technically impair the reception of
DAB programming. We seek comment on whether an analogous regulatory framework would be
appropriate for the radio broadcast service and the limits, if any, we should establish for ancillary
services.
19. (7) Extensibility. We believe that a DAB system design also must be adaptable to future
technological advances. As Lucent puts it, a DAB system should be structured "with 'headroom'
to allow incorporation of future technological advances." We tentatively conclude that
extensibility is crucial to preserving a strong and competitive free, over-the-air broadcast system in
a digital communications environment, and to ensuring that listeners receive the full benefits of
DAB. We seek comment on this view.
20. (8) Accommodation for existing broadcasters. We tentatively conclude that any DAB
system should, to the maximum extent possible, accommodate all existing broadcasters that desire
to initiate DAB system transmissions. A digital service that permits both AM and FM stations to
provide the same level of enhanced audio quality also would be of significant benefit to
broadcasters and listeners. We tentatively conclude, however, that placing AM and FM
broadcasters on equal footing in terms of signal quality is not an essential DAB technical
requirement. A digital AM service that would provide "FM-like" audio quality would create
important new format choices for AM stations and could help revitalize this service. We seek
comment on these views.
21. (9) Coverage. Broadcasters argue that any DAB system should be capable of replicating
existing coverage areas. Such coverage areas tend to be greater than the "interference-free" areas
protected under the Commission's rules. We recognize that preserving existing coverage areas
may be an important aspect of ensuring a non-disruptive transition to DAB. Nevertheless, we
tentatively conclude that the public interest is best served through the development of a digital
radio assignment policy that adopts current analog protected service contours for DAB. The
Commission has recognized in several different contexts that stations generally provide useful
service beyond their service contours in the absence of interference. However, service contours
are not merely a function of the distance at which adequate reception is possible. Rather, these
contours reflect a balance between providing adequate service areas and expanding the potential
number of station assignments. We believe that this longstanding policy is applicable here. We
request comments on these views.
22. (10) Implementation costs/affordability of transmission and receiver equipment.
Minimizing implementation costs of any DAB model and/or system is a fundamental means of
ensuring a rapid and non-disruptive transition to DAB. One important benefit of an IBOC model
appears to be its ability to allow broadcasters to build on the existing broadcast infrastructure in
transitioning to a DAB system. With regard to affordability, the Petition points out that the
relatively low cost of receivers contributes to the radio broadcast service's unmatched
penetration. We wish to consider the costs to consumers of digital receivers as well, including the
trade-offs between receiver performance and cost.
23. We seek comment on all of these proposed evaluative criteria. As is the case with our
public policy objectives, we recognize that these criteria conflict in certain respects, and that the
Commission will be required to balance competing interests. We also recognize that the IBOC
model and other possible models have specific benefits and drawbacks with regard to the various
criteria. In applying these criteria, we seek to identify the DAB model or models that best would
serve the public interest.
X. IBOC DAB Model.
25. Proponents contend that IBOC technology represents the best means of implementing DAB
in the United States. They note its promise of superior audio fidelity, signal robustness, and new
and improved ancillary services. They also contend that IBOC technology would be spectrally
efficient, in that it would not require a new spectrum allocation, and consequently,
"administratively efficient" because this approach would not raise new spectrum allocation and
licensing issues. Moreover, they argue that IBOC technology would ensure a fast and seamless
transition from analog to digital by providing a digital opportunity for all existing broadcasters.
According to proponents, broadcasters could introduce digital service immediately without
disrupting existing analog service, but also would have the flexibility to "upgrade to digital at their
own pace" based on "the economic needs of local stations and local listener demand[.]" Listeners
would enjoy uninterrupted service with their analog receivers. IBOC proponents also contend that
DAB implementation costs would be minimized because IBOC transmission systems could be
integrated into the existing broadcast infrastructure in accordance with "the normal life and
maintenance cycle of radio broadcasting equipment. Finally, they contend that IBOC would
enable stations to preserve their current frequency identities and coverage areas, service features
that are important to broadcasters and would promote a non-disruptive transition to DAB service.
26. We believe that these arguments have merit and that a workable IBOC system would be
superior to a new-spectrum DAB system in several respects. It would not require new spectrum.
It would permit a fast transition to DAB that preserves the benefits of the existing radio broadcast
service while leveraging the considerable resources and expertise of the radio broadcast industry.
IBOC systems also may achieve certain spectrum efficiencies. They may be able to provide
enhanced sound quality, permit significant expansions in station service areas, and create
opportunities to introduce a broad range of ancillary services. Continuing advances in compression
technology may permit even greater levels of information transmission, and thus, the introduction
of new broadcaster services. Moreover, if proponents' claims are correct, the enhanced robustness
of IBOC systems could help eliminate or ameliorate interference now experienced by grandfathered
short-spaced radio stations and the other types of signal degradation suffered by many stations
operating in difficult or congested RF environments. To ensure the smooth initiation of DAB
service by existing broadcasters, we tentatively conclude that if IBOC is adopted, IBOC DAB
licenses will not count as distinct authorizations for purposes of our local radio ownership
restrictions. We seek comment on these views.
27. However, an IBOC approach also raises spectrum efficiency concerns. Current IBOC
system designs are premised on doubling the bandwidth licensed to AM and FM stations to 20 kHz
and 400 kHz, respectively, spectrum which is currently included under current "emission masks."
We recognize that the additional bandwidth for digital sidebands is an inherent feature of the IBOC
hybrid mode. However, the IBOC system proponents envision that AM and FM stations would
retain the additional bandwidth in an all-digital operating environment. A permanent expansion
of the channel bandwidth might constitute a fundamental change in spectrum assignment
principles. We note that, on the other hand, current use of the frequencies to be occupied by the
digital sidebands is effectively precluded by analog transmission technology and radio receivers
now in service. We seek comment on the spectrum efficiency of the current IBOC system designs
generally and, in particular, on using 400-kHz FM and 20-kHz AM channel bandwidths in the all-
digital IBOC mode. We also seek comment as to whether a signal architecture that shifts audio
carriage from sidebands to a center band in an all-digital environment is inherently more spectrally
efficient than one which continues to operate on the basis of sidebands. We invite the IBOC
system proponents to comment on the need for the sidebands in the all-digital mode. We also
seek comment on whether spectrum may be returned at the end of the licensees' IBOC transition to
all-digital broadcasting.
28. The claimed advantages of the IBOC technology to maintain coverage at lower power
levels, to permit significant power increases when all-digital operations are initiated, and to provide
substantially enhanced robustness from interference and signal degradation create possibilities
for existing broadcasters to increase service areas significantly and for new station opportunities
which are not possible within the current analog technical and regulatory framework. We recognize
that the current IBOC model may provide incumbent broadcasters with a strong incentive for a
rapid transition to all-digital service. We seek comment on this model. How do we balance the
need to provide broadcasters with sufficient incentives to transition rapidly to DAB with the need
to respond to the unmet demand for new entrants? We seek analyses of the minimum power levels
that would preserve service within protected service areas in an all-digital environment, and
alternatively, the levels that would not result in significant disruptions to current listening patterns.
Commenters should consider the different implications of an IBOC approach over the short-term
transition period, when hybrid transmissions require greater bandwidth, and the long-term, when
the absence of analog transmissions could open up spectrum for new entrants.
CC. Alternative DAB Model Utilizing New Spectrum.
30. In GEN Docket No. 90-357, we also considered the potential for allocating new spectrum
for terrestrial digital audio broadcasting. We stated that while we wished to encourage technical
innovation and the development of new services, such as DAB, we must weigh these factors
against competing demands for use of the spectrum. We further stated that we must judge the
benefits of DAB service against the needs of other existing and proposed new services. We
indicated that we intended to consider whether a new frequency allocation should be provided for
terrestrial DAB and specifically whether to use a portion of the existing television band for this
service. At that time, however, we also raised the concern about whether such a DAB allocation
would impact our desire to accommodate the implementation of digital television services. Now,
with the completion of the plan for the introduction of DTV, we believe that it may be possible to
use a portion of the television spectrum for DAB.
31. We therefore request comment on whether the six megahertz of spectrum at 82-88 MHz,
currently used for TV Channel 6, could be reallocated to DAB service at the end of the DTV
transition. We seek comment on whether this spectrum could be reallocated without adversely
affecting the broadcast television service. We also recognize, however, that a Channel 6 allocation
could significantly delay the introduction of DAB. The earliest this spectrum will be available in
many areas is 2007. However, the exact date of spectrum availability, which is tied to the end of
the DTV transition period, could be significantly later. Thus, it appears that proven IBOC
systems could be operational significantly sooner than an approach which relies on the availability
of spectrum at 82-88 MHz. We request comment on all aspects of this new-spectrum DAB
approach and ask interested parties whether there are other frequency bands that might be more
desirable for new DAB spectrum. We note that the IBOC and new-spectrum DAB options need
not be mutually exclusive and, in fact, could be complementary.
32. The new spectrum approach would permit the use of a DAB system that is completely
independent of the existing analog AM and FM radio systems. We request comment on whether
independence from existing AM and FM radio systems would provide greater flexibility in
planning and implementing DAB service. An independent DAB transmission system might operate
at a higher data rate and thereby support higher audio quality and enhanced ancillary services as
compared to an IBOC system operating in hybrid mode. We seek comment on these matters.
33. Any reallocation of the 82-88 MHz band for DAB service should facilitate the transition to
a final DAB spectrum plan that would include the existing FM radio spectrum. For example, when
DAB is accepted by consumers and proves successful, the existing adjacent FM spectrum at 88-
108 MHz could be converted to DAB. Under such a plan, all existing analog FM stations would be
permitted to switch their operations to digital service on their existing channels. However, such a
transition could result in significant service disruptions. It would require broadcasters to choose
between serving listeners with analog receivers or listeners with digital receivers. Significant
listener dislocations could occur at the point of a "hard" transition to digital transmissions unless
everyone has acquired a digital radio, which in turn depends on the cost-effective manufacture of
digital receivers and widespread consumer acceptance of these devices. We seek comment on these
transition issues.
34. We note that the DTV Table of Allotments includes only one Channel 6 allotment for the
United States. There are 57 existing analog television stations on Channel 6. These analog
stations are scheduled to cease operation after 2006 or the end of the DTV transition period. We
seek comment on whether this reallocation would adversely impact DTV implementation or
broadcast television service in general.
35. We request comment on the appropriate bandwidth for DAB channels in a new spectrum
context. Should any new spectrum assignments reflect the same channel assignment scheme
currently used with the FM service? Would using the FM channel plan facilitate the eventual
conversion of the existing FM stations to DAB operation, and a common FM/DAB radio receiver
design across the entire 26 MHz of spectrum from 82-108 MHz? We also seek comment on
whether a common FM/DAB channel scheme and receiver design would facilitate a transition plan
in which existing FM stations could determine on their own when to switch to digital operation
without regulatory intervention. We also invite interested parties' suggestions for alternative DAB
channel plans.
36. If we adopt a new-spectrum option, should we adopt a service area approach that would
follow the plan of the existing classes of FM stations, i.e., Class A, B1, B, C3, C2, C1, and C, or
should all DAB stations be provided a common service area? Parties favoring different size
services areas are also requested to comment on how channels should be apportioned among the
various classes.
37. Should all AM and FM broadcasters be eligible for a DAB license in any new spectrum
made available? Should we exclude DAB licenses in the new spectrum from the local ownership
limits that apply to analog stations? To what extent should new channels be reserved for
educational use and new entrants? Should we limit each applicant to a maximum number of DAB
licenses in each market? How would the issuance of these licenses implicate our statutory
requirements with respect to auctions?
38. We also request comment on what approach or approaches could be used to specify the
initial DAB channel allotments under a new spectrum approach. One approach could be to allot
DAB channels to communities in proportion to the number of AM and FM channels operating in
each community using allotment software similar to that used in creating the initial DTV channel
allotments. Another approach could be to allot DAB channels to communities based on an initial
expression of interest by applicants. We seek comment on whether these approaches would be
consistent with the requirement for the fair, efficient and equitable distribution of radio service in
Section 307(b) of the Communications Act, as amended. We also request comment with regard
to how to assess the technical acceptability of new DAB allotments and modifications of DAB
allotments. Specifically, we request comment on whether to use an approach that uses minimum
geographic spacing distances similar to what is now used for FM stations or an approach that
that uses engineering criteria to show that an allotment does not cause additional interference to
other allotments.
39. As a further alternative, we seek comment on whether Channel 6 spectrum should be used
to ensure adequate new entrant DAB opportunities. We seek comment on whether we may give
preferences to LPFM licensees in assigning this Channel 6 spectrum, and if so, whether we should
do so in the event we authorize an LPFM service. As we stated above, we are concerned about
the interrelation between DAB and the proposed LPFM service, including a DAB system that
utilizes Channel 6. Although we "do not intend to create a low power radio service on any
spectrum beyond that which is currently allocated for FM use," we seek comment on the extent to
which a DAB system established on Channel 6 could ensure adequate new entrant opportunities.
We note that the Channel 6 LPFM and IBOC proposals could be treated as complementary digital
transition strategies.
NN. Standards and Testing.
1. DAB Transmission Standard.
2. In its Petition, USADR asked the Commission to adopt a DAB transmission standard, and
submitted a report arguing both that there is a need for such a standard and that the radio
broadcast industry is unlikely to be able to develop one on its own. Most commenters agreed
that a single standard is necessary and that the Commission has a critical role in establishing
one. Among other things, commenters argued that a single standard is necessary to provide the
certainty that consumers, licensees and equipment manufacturers would need to justify their
investment in DAB technology. They also predicted that industry attempts to reach a consensus
on a voluntary standard would be impeded by the number of parties involved and their differing
interests and agendas. Several pointed to the AM stereo experience as an example where similar
circumstances prevented the implementation of a single, voluntary standard. In addition, a
number of commenters cited the Commission's adoption of a DTV transmission standard as
precedent for a similar action in this proceeding.
3. In the DTV proceeding, we observed that the traditional rationale for mandating a standard
arises when two conditions are met: first, there would be a substantial public benefit from a
standard; second, private industry either will not, or cannot, achieve a standard because the private
costs of participating in the standard-setting process outweigh the private benefits, or a number of
different standards have been developed and private industry cannot reach consensus on a single
standard. The Commission, in fact, did identify the same kind of considerations in support of
adopting a mandatory DTV standard that commenters now argue support the adoption of a
mandatory DAB transmission standard. We noted that mandated standards might provide needed
certainty to consumers, licensees, and equipment manufacturers, particularly where the launch of a
new technology is involved. Moreover, we reasoned that standard-setting would help obviate the
"chicken and egg" dilemma that can impede the introduction and acceptance of new technology and
impose additional costs on consumers. We also recognized, however, that mandatory standards
can have drawbacks, including potential deterrence of technical innovation particularly where a
technology is new and further development can reasonably be anticipated to occur and
curtailment of some forms of competition.
4. We tentatively conclude, as we previously found in the DTV proceeding, that the public
interest compels a Commission role in the development of DAB transmission standards, "with the
advice and involvement of all sectors of the industry." We lack sufficient information at this
time, however, to conclude that a Commission-mandated DAB transmission standard is necessary.
With regard to the first of the above-stated conditions for establishing a standard, the Commission
seeks further comment on the desirability of a single DAB transmission standard. For example, it
may be the case that there is a high degree of compatibility among the several DAB systems.
Thus, there may be little public benefit derived from a mandated standard. In addition,
developments in digital signal processors ("DSPs") may have obviated the need for a DAB
standard or may justify a voluntary or technically narrower approach. We seek comment on these
matters. Is an "open architecture" approach feasible? What technical and economic impacts
would such an approach have on the development and manufacture of DAB receivers? Have
advances in DSP chip technology made a standard unnecessary?
5. With regard to the second of the above-stated conditions, it is too early to predict whether
private industry can or will be able to achieve a voluntary DAB transmission standard.
Nevertheless, this Notice identifies numerous public policy issues concerning both terrestrial DAB
and its potential impact on our vital radio broadcast service. Again, we seek further comment on
this issue. How likely is the broadcast industry to establish a de facto standard in the absence of
Commission action? Can the Commission take actions short of mandating a standard in order to
help the industry establish a standard, for example by conferring benefits to licensees utilizing the
standard? Furthermore, should we decide that a Commission-mandated standard is necessary,
what should be the constituent elements of such a standard?
6. Decision-Making Models for DAB System Testing, Evaluation and
Transmission Standard Selection.
7. In response to the USADR Petition, commenters suggested a number of models for DAB
system testing, evaluation and transmission standard selection. The NAB, for example, proposed
an industry-based model, whereby the NRSC would test and evaluate competing IBOC systems,
select a transmission standard based on industry consensus, and make recommendations for the
Commission to adopt. Lucent argued that the Commission must actively participate to ensure a
fair and unbiased decision-making process. Ford proposed the creation of a public-private
committee with open membership, which would achieve consensus and even recommend a specific
transmission standard for adoption by the Commission. Ford argued that this model would
enable the Commission to conserve its own resources and utilize private sector expertise.
8. A committee similar to that proposed by Ford played an important role in the adoption of a
DTV standard in Docket No. 87-268. The Advisory Committee on Advanced Television Service
("ACATS") was established to assist the Commission "in considering the issues surrounding the
introduction of advanced television service in the United States[,]" and its charter specified that it
would "recommend policies, standards and regulations that would facilitate the orderly and timely
introduction of advanced television services." We relied heavily on the ACATS to test and
evaluate competing advanced television ("ATV") systems in the first instance. It also proved to be
effective in facilitating participation by a broad range of stakeholders and achieving industry
consensus on a transmission standard. There are important differences between Docket No. 87-
268 and this proceeding, however, that must be considered in connection with the possible
establishment of an advisory committee. Docket 87-268 considered a wide array of ATV
technologies, including DTV, in their early stages of development. In contrast, DAB systems now
are being deployed in Europe and Canada, and IBOC systems, according to proponents, are in the
final stages of development. Moreover, it may be possible to implement DAB service much more
rapidly than DTV service, due to IBOC systems' promised compatibility with existing analog
signals. Thus, there may be a question as to whether an advisory committee would be capable of
acting with due speed in the context of this proceeding.
9. With regard to the narrower issue of IBOC DAB system testing, USADR and Lucent have
asserted in recent ex parte meetings with staff and in written submissions that the Commission
should establish certain procedures immediately. They disagree, however, as to the specifics of
such procedures. USADR urges us to endorse the NRSC testing program and to request that
proponents file their NRSC test reports with the Commission on the NRSC deadline of December
15, 1999. USADR contends that the reports will enable us to identify the field of proponents and
address threshold performance questions such as improved audio quality, compatibility with
existing analog service and equal coverage. Lucent, on the other hand, criticizes the NRSC testing
program as potentially subject to manipulation because of the lack of a common testing platform,
and argues that the data it yields will be insufficient to meaningfully evaluate the performance of
different system designs. Lucent proposes that the Commission convene a meeting of USADR,
Lucent and DRE (the three known IBOC system proponents) to facilitate agreement on a revised
testing program that, in Lucent's view, should be conducted by a common entity, observed by the
Commission staff, and sufficient to permit us to comprehensively evaluate the proponent systems
in the context of this proceeding. In short, rather than a multi-step process, Lucent envisions a
single round of tests sufficient to enable us not only to determine the viability of IBOC systems but
to select a superior system. However, Lucent reportedly has reached an agreement with the NRSC
recently which provides for a second stage of comparative testing of each IBOC system on a
common testing platform.
10. In GEN Docket No. 90-357, the Commission relied on the NRSC and CEMA to test
IBOC and other DAB systems. This proved to be a wise course: tests proved that IBOC
technology was not yet viable, so that Commission action would have been premature. We
applaud the recent efforts of these groups to develop testing guidelines, and will continue to rely on
them to facilitate and evaluate the development of IBOC DAB systems. We anticipate that the first
stage of the NRSC's current program will serve a useful, if limited, purpose. We request each
proponent to submit a copy of its test reports to the Commission as part of the record in this
proceeding. We emphasize that all test data relevant to our evaluation of IBOC and/or other DAB
systems will be subject to public comment and close staff scrutiny. We also see merit in a second
stage of comparative testing of IBOC systems on a common testing platform.
11. We believe that it is necessary and appropriate to rely to some degree on the expertise of
the private sector for DAB system evaluations and, ultimately, recommendations for a transmission
standard. Each of the testing models discussed above would help facilitate broad participation in
this process. However, we conclude that it is premature to commit ourselves to any particular
approach. This decision is based on both the limited information we have on the performance
capabilities of the competing systems and the fact that system proponents appear to be actively
working toward a consensus on comparative testing issues. Nevertheless, we note that the NRSC
brings substantial experience, expertise, and credibility to the testing process. Their current
initiatives may provide the best opportunity for the rapid introduction of DAB. Moreover, the
Commission would give great weight to any industry compromise the NRSC may achieve. We
plan to monitor this testing process closely for fairness, thoroughness, and timeliness. While we
are encouraged by the NRSC's efforts to date, we will act promptly to provide an alternative
mechanism if subsequent events undermine our confidence in the current testing process. In this
regard, we expect to revisit the effectiveness and appropriateness of the NRSC approach once the
Commission has reviewed the NRSC report regarding IBOC tests, which we expect to be some
time in the first quarter of 2000. In the meantime, we wish to develop a complete record on these
issues in order to be in a position to take informed and expeditious action at the proper time. We
therefore seek comment on the evaluative models discussed above and any others that may merit
consideration.
XII.ADMINISTRATIVE MATTERS
13. Filing of Comments and Reply Comments. Pursuant to Sections 1.415 and 1.419 of the
Commission's Rules, interested parties may file comments within seventy-five (75) days of the
date of publication of this Notice in the Federal Register, and reply comments within one hundred
and five (105) days of the date of publication of this Notice in the Federal Register. Comments
may be filed using the Commission's Electronic Comment Filing System ("ECFS") or by filing
paper copies.
14. Comments filed through the ECFS can be sent as an electronic file via the Internet to
. In completing the transmittal screen, commenters should
include their full name, postal service mailing address, and the applicable docket or rulemaking
number. Parties may also submit an electronic comment by Internet e-mail. To get filing
instructions for e-mail comments, commenters should send an e-mail to ecfs@fcc.gov, and should
include the following words in the body of the message, "get form